Chitosan/carrageenan nanoparticles: Effect of cross-linking with tripolyphosphate and charge ratios

► Charge ratios play a critical role on nanoparticle formation mechanism. ► Tripolyphosphate reduces size of chitosan/carrageenan nanoparticles. ► Tripolyphosphate improves nanoparticle shelf-life, lasting at least 9 months.